Environmental officials closed several state park beaches to swimmers on Tuesday.

The Department of Energy and Environmental Protection said the beaches at Silver Sands in Milford, Indian Wells State Park in Shelton, Kettletown State Park in Southbury, Wadsworth Falls State Park in Middlefield and Wharton Brook State Park in Wallingford were off limits.

DEEP said the water tested positive for indicator bacteria.

It said that kind of bacteria are not disease-causing pathogens, but are one of the tools used by public health and environmental protection authorities to evaluate the potential for contamination of water bodies.

DEEP said the state parks themselves remain open for other activities. Only the water is affected.